# numeric value – How to make the InverseBetaRegularized function behave the same way in Mathematica 11.3 compared to 11.2?

In Mathematica 11.3:

``````InverseBetaRegularized[0.001, 4501, 500]
``````

Never finish the calculation.

``````InverseBetaRegularized[0.001`50, 4501, 500]
``````

Makes "Undetermined" (which is a wrong result), but also warnings:

"Power :: infy: Infinite Expression 1/0 ^ 500 met."

"Infinity :: indet: Undetermined expression 0 ComplexInfinity encountered."

Trying to do the exact calculation and then rounding it does not work either:

``````Ground[10^16*InverseBetaRegularized[1/1000, 4501, 500]]/ 10 ^ 16
``````

Return the entry as it is and give the warning

``````Floor :: meprec: Internal precision limit \$ MaxExtraPrecision = 50.` reached when evaluating Floor[10000000000000000 InverseBetaRegularized[1/1000,4501,500]].
``````

The same error occurs even if I raise MaxExtraPrecision to 1000. If I increase it continuously, the calculation takes longer, and then the error message fails.

There are several other cases where InverseBetaRegularized gives errors or never completes the calculation. In Mathematica 11.2, the function is much better:

``````InverseBetaRegularized[0.001, 4501, 500]
``````

Gives 0.88646

``````InverseBetaRegularized[0.001`50, 4501, 500]
``````

Gives 0.886460350710515650598296037307790832086968197199659

``````Ground[10^16*InverseBetaRegularized[1/1000, 4501, 500]]/ 10 ^ 16
``````

Given `4432301753552759/5000000000000000`